Clamp



' Dec. 8, 1959 c J RENFROE ET AL 2,915,321

CLAMP Filed Aug. 28, 1958 INVENTORS, C22 arles I901: free, fiymond L Ken froe ATTORNEYS CLAlVIP Charles J. Renfroe and Raymond L. Ren fro'e, Jacksonville, Fla.

Application August 28, 1958, SerialNo. 757,828

7 Claims. (Cl. 294 -101) This invention relates to a clamp to be "attached to hoisting apparatus for lifting heavy plates and other similar objects.

An object of the invention is to provide a clamp which automatically attaches itself to a plate or other similar object whereby the plate may be transported from one location to another. The clamp, therefore, automatically locks itself to the plate or other object when the load is applied and at whatever angle it is applied, i.e. whether the load is applied by presenting it to the "clamp with its principal surfaces in a vertical plane or at an angle to such a vertical plane.

Another object is to provide a clamp of the type described which consists of a minimum number of parts and which is rugged in construction and positive in-operation.

A further object is the provision of a clamp having a fixed jaw and a movable jaw, the "movable jaw being automatically operated from open to closed position when the clamp is held suspended from a hook or other connecting member forming part of a hoisting mechanism.

An additional object is the provision of a clamp with a movable jaw which'engages the load more firmly when handling heavier loads, so that the heavier the load or weight of the plate 'to be lifted, the more firmly "the -same is grasped by the movable jaw of the clamp.

Other objects will appear hereinafter throughout the specification.

In the drawings:

Figure 1 is a side elevational view of the clamp;

Figure 2 is a view similar to Figure 1, taken on the line 22 of Figure 3; and

Figure 3 is an end elevational view of the clamp shown in Figure 1.

It will be understood that the clamp is adapted to be vertically suspended by a hook or other holding means forming part of a hoisting mechanism, and that the plate or other object to be grasped by the clamp will be presented edgewise to the clamp. It will be further understood that one or more clamps of the type illustrated in the drawings and to be described hereinafter may be used for the purpose of lifting the plate from one position to another. In other words, the plate may be transferred from one location in a yard, plant, or other place of storage, to another location within the said yard, plant, etc.

Referring to the drawings, shows the housing which preferably is of a single casting. The housing 10 is provided with parallel, spaced, platelike sides 12 and 14, and an integral connecting web 16. The platelike sides 12 and 14 are provided with aligned openings 18 and 20 forming upwardly extending slots as shown in Figure 1, respectively, for the reception of the object to be lifted, such as a plate.

Located midway of the length of the housing 10 is a pivot member 22 comprising a bolt having a head 24 nited States Patent 0 2 and a threaded nut 26. The bolt is provided with a spacing collar 28. Pivotally mounted on the bolt are a pair of actuating links 30 and 32, which links are identical in structure. The links are connected to each other at their ends by a pair of rivets. These rivets are movable with the links 30 and 32. Rivet 34 connects hook link 38 to actuating links 30 and 32, the shank 40 of the supporting link, such as a hook link 38 extending between the ends of links 30 and 32, as seen in the several figures. The supporting link or hook link 38 is provided with an aperture 42 by which it is suspended from a hook, not shown, of a hoist, and the hook link is provided with an intermediate curved neck portion 44 having a surface 46 which is adapted 'to engage the stop pin 48 to prevent the housing 10 from tipping excessively with relation to 'the hook link 38 in one direction. Excessive tipping in the opposite direction of the housing is prevented by engagement of the nose 50 on said hook link which engages the spacing collar 28 as seen in Figure 3.

It will be noted, therefore, that pivot member 22 and stop pin 48 prevent excessive pivotal movements in either direction of the housing 10 with relation to the hook link'38.

The movable jaw '52 is pivotally mounted on the "pin 54. This pin may be provided with a head 56 at one end, and the opposite end of this pin, indicated at 58, is provided with an aperture 60 for the reception of a cotter pin62.

The pivoted jaw '52 is provided with a slot 64 for the reception of thepin or stud 36, which connects links 30 and 32. These links 30 and 32 move as one and each comprises a bell crank lever, actuated by supporting link 38, as'clearly seen in Figures 2 and 3.

When the supporting 'or hook link 38 is moved upwardly, as viewed in "Figure 2, this movement causes rotation of the bell crank or actuating links 30 and 32 in a "clockwise direction, thereby forcing the jaw 52 'to move in a counter-clockwise direction on pivot pin 54, from -the position shown in Figure 2 to that shown in Figure 1, or to a work-engaging position, assuming a workpiece has been inserted in the opening 18, 20.

Mounted on the anvil portion 66 of the web 16 is a stationary jaw 68. This anvil portion is mounted on a shank 70 having a screw threaded end which is held in place by a nut 72 located in a recess of the web 16.

It will be understood that in practice the clamp will be suspended in a position with its longitudinal axis extending vertically. In this position the opening 42 is engaged by a hook which is suspended from a hoist. As soon as the hook engages the opening, the weight of the parts will cause the movable jaw to close. When applying the clamp to the vertical side surface of a heavy plate which is standing in a substantially vertical position, the hook may be lowered to a position where the housing will be engaged by the hands of an operator who will push upwardly on the housing to cause the parts to assume the position shown in Figure 2. In this position the aligned openings 18 and 20 are moved over the upper edge of the plate so that the movable and stationary jaws are in position for engagement with the side faces of the plate. Then when the hook is elevated, the movable jaw 52 moves in a counterclockwise direction to cause the plate to be engaged between the fixed and movable jaws 68 and 52. The heavier the plate, the more firmly will the same be grasped by these jaws.

After the plate has been moved to another location, the jaws may be easily released from the plate by moving the clamp downwardly, the plate or other object being supported on the ground or otherwise supported at its destination. Thus the downward movement of the clamp frees the jaws from the plate when the latter rests against or is supported by a solid object.

It will be noted by reference to Figure 2 that the lower end of the hook link 38 and the upper ends of the actuat-,

ing links 30 and 32 abut against a curved shoulder 74 forming a part of the Web 16. This prevents the hook link from moving too far downwardly into the space between the platelike sides 12 and 14.

The above description and drawings disclose a single embodiment of the invention, and specific language has been employed in describing the several figures. It will, nevertheless, be understood that no limitations of the scope of the invention are thereby contemplated, and that various alterations and modifications may be made such as would occur to one skilled in the art to which the invention relates.

We claim:

1. A clamp comprising a housing having sides, said sides having aligned substantially transverse work receiving openings forming an upwardly extending slot when the longitudinal axis of said casing is in a vertical plane, a first jaw, means pivoting said jaw in said casing adjacent one side of said slot for movement in said slot whereby to engage the work, means for moving said first jaw into and out of work-engaging position including a bell crank lever means having ends and means pivotally supporting said bell crank lever means in said casing intermediate said ends, one end of said bell crank lever means and said first jaw comprising members, one of said members having a stud and the other of said members having a slot into which said stud extends, actuating link means adapted to support said casing with its longitudinal axis in a vertical plane, said bell crank lever means and said first jaw being substantially confined within the said housing, means pivotally connecting the lower end of said actuating link means to the opposite end of said bell crank lever means from the said end connected to said pivoted first jaw, and a second jaw located on the opposite side of said slot from said first jaw, whereby when the work is inserted between said 'first and second jaws and said actuating link means is moved in a vertical direction said bell crank lever means and said first jaw are rotated on their pivots to cause engagement of the 4 work between said first and second jaws, said means for pivotally supporting said bell crank lever means, said pivot means for said first jaw, said stud and said means pivotally connecting said actuating link means to an end of said bell crank lever means all being located parallel to each other in said casing.

2. The structure of claim 1 wherein said stud is located on an end of said bell crank lever means and said slot is located in said first jaw.

3. The structure of claim 1 wherein said bell crank lever means comprises a pair of levers, said actuating link means having a lower portion extending between said pair of levers at the point of pivotal connection between said bell crank levers and said actuating lever lower portion.

4. The structure of claim 1 wherein said casing is provided with a stop pin located adjacent to and on the opposite side of said actuating lever from said means for pivotally supporting said bell crank lever means whereby said stop pin and said last named means prevent excess lateral movement of said actuating lever.

5. The structure of claim 1 wherein said casing is provided interiorly between said sides and above said slot with a shoulder for limiting the downward movement of said actuating link and the rotation of said bell crank lever means to a point where said stud would disengage itself from said slot.

6. The structure of claim 1 wherein in a pair of lower ends at least one of said ends is downwardly and inwardly tapered toward said first named slot.

7. The structure of claim 1 wherein said second named slot extends substantially radially outwardly from the said means pivotally supporting said first jaw.

References Cited in the file of this patent UNITED STATES PATENTS 2,618,505 Rosenbaum Nov. 18, 1952 2,654,631 Renfroe Oct. 6, 1953 2,852,300 Gardner Sept. 16, 1958 FOREIGN PATENTS 139,174 Sweden Feb. 17, 1953 

